1. Priority Claim
This application claims the benefit of priority to EP 06016029.8, filed Aug. 1, 2006, which is incorporated herein by reference.
2. Technical Field
The present inventions relate to a dereverberation system for use in a signal processing apparatus and, more particularly, to a dereverberation system that may be used in a loudspeaker-room-microphone environment.
3. Related Art
Signal processing systems are used in many applications. One set of applications includes speech signal processing/recognition, where the signal processing system may be used to enhance the intelligibility of the speech signals. Another application is the enhancement of the quality of signals transmitted and/or received in a communication system. Signal processing in these systems may be used for noise reduction as well as echo compensation.
A microphone may be used in a reverberant environment. A microphone used in such environments may detect audio signals that are generated by an audio source directly and delayed reflections. The signals received at the microphone may be smeared over time as a result of the environmental acoustics that generate a reverb response. Reverberation signals at a microphone are noticeable in an office, a vehicle, dealer cabin, or other enclosed space, and may reduce the intelligibility of the desired microphone signal, such as a target speech signal.
One method of dereverberating a microphone signal is deconvolution. In this method, the microphone signal is inverse filtered using an estimate for the acoustic channel response. Accurate dereverberation depends on an accurate estimate of the acoustic channel response, which can be difficult to ascertain.
Another method of dereverberating the microphone signal process the direct-path speech signal uses pitch enhancement or a predictive coding. This method is a multi-channel approach that averages multiple microphone signals to obtain a reduction of the reverberation contribution to the processed signal. However, implementation of this multi-channel approach may be expensive and require many hardware components. Although various dereverberation systems have been contemplated, the contemplated systems suffer from various deficiencies.